Characterization of 3D-printed gelatin/sodium alginate/58S bioactive glass scaffold and osteogenesis in rabbit cranial defects

Critical-sized maxillofacial bone defects often lead to delayed healing or non-union, necessitating clinical intervention with osteoconductive biomaterials. 58S bioactive glass (BG) is a promising candidate to release osteogenic ions (Si, Ca, P). In the present study, a dualnetwork scaffold was fabricated via 3D printing using a bioink composed of gelatin (Gel), sodium alginate (SA), and 58S BG (mass ratio 10:4:7). The scaffold's physicochemical properties, biocompatibility, and osteogenic efficacy were systematically evaluated. The scaffold demonstrated favorable structural characteristics with a high porosity of 76 ± 1% and a compressive Young's modulus of 166.3 ± 1.6 kPa. It exhibited a volumetric swelling ratio of 85.7 ± 13.1% and maintained 62% of its initial mass after 14 weeks in simulated body fluid, indicating excellent stability and controlled degradation. Subcutaneous implantation in nude mice revealed no signs of inflammation or fibrous encapsulation at 4 and 8 weeks, confirming its excellent biocompatibility. In a critical-sized rabbit calvarial defect model, micro-CT analysis after 6 months showed that the scaffold group achieved a bone volume fraction (BV/TV) of 46.8 ± 1.2%. This result was comparable to the Bio-Oss (48.7 ± 3.1%), with no residual scaffold particles observed, confirming its complete biodegradation synchronized with new bone formation. In conclusion, this biodegradable Gel/SA/58S BG scaffold combines favorable printability, structural stability, high bioactivity, and well-matched degradation kinetics, presenting a highly promising and translatable platform for the personalized reconstruction of maxillofacial bone defects.